Variation in target and distractor heterogeneity impacts performance in the centroid task

Lu, Vivian; Wright, Charles E.; Chubb, Charles; Sperling, George

doi:10.1167/19.4.21

Cited by 5 publications

(2 citation statements)

References 31 publications

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“…Several previous studies provide support for the idea that subjects have separate access to red and green half-axis mechanisms (see, for example [17]…”

Section: Introductionmentioning

confidence: 79%

Color scrambles reveal Red and Green half-axis mechanisms plus a mechanism selective for low chromatic contrast

Herrera¹,

Chubb²,

Wright³

et al. 2020

Preprint

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In this paper we set up to enumerate and characterize mechanisms sensitive to color scrambles. A color scramble is a texture made of a finite number of elements drawn from a set Ω, in this case small colored squares, distributed according to a histogram. We use a novel method to derive a eight equiluminant lights along the Red-Green cardinal axis. We then generate a background annulus and a target disk to be detected in one of eight pre-defined locations. We modeled the mechanisms available to the subjects to do the task using the seed-expansion weighting procedure. This theory-free, data- driven approach, constrained only by the size of the set Ω, makes no assumptions about the number of mechanism used to perform the task, or about what they are sensitive to. We found that a model of three mechanisms explains well the data: one half-wave rectified mechanism sensitive to green, one half-wave rectified mechanism sensitive to red, and a mechanism sensitive to gray. We discuss the implications of this result.

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“…Several previous studies provide support for the idea that subjects have separate access to red and green half-axis mechanisms (see, for example [17]…”

Section: Introductionmentioning

confidence: 79%

Color scrambles reveal Red and Green half-axis mechanisms plus a mechanism selective for low chromatic contrast

Herrera¹,

Chubb²,

Wright³

et al. 2020

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…The authors call the perceptual value of each patch "weight," which seems appropriate for a centroid computation. However, Rodriguez-Cintron, Wright, Chubb, and Sperling (2019) and Lu, Wright, Chubb, and Sperling (2019) use the term "influence" for the scalar value used to describe items in their centroid computations.…”

Section: Discussion: Partmentioning

confidence: 99%

Multiple concurrent centroid judgments imply multiple within-group salience maps

Sun

Chu

Sperling

2021

Atten Percept Psychophys

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Subjects viewed a brief flash of 8-24 dots of either two or three colors randomly arrayed. Their task was to move a mouse cursor to the centroid (center-of-gravity) of each color in a pre-designated order. Conventional and idea-detector analyses show that subjects accurately judged all three centroids utilizing an astounding 13/24 stimulus dots, with only a modest loss of accuracy compared to judging a single-predesignated color centroid. The ability to concurrently compute three centroids is important because it is believed that centroid judgments are made on salience maps that record only salience and are ignorant of the features that produced the salience. Our explanation, instantiated in a computational model of salience processing, is that subjects have three salience maps. Dots are initially segregated into three groups according to color, then each color-group is recorded on a different salience map to compute a centroid. In Part 2, the data are analyzed in terms of Attention Operating Characteristics to characterize impairments in subjects' color-attention filters (mostly insignificant) and encoding efficiency (20% drop for the hardest task) in making multiple versus single centroid judgments. A new, more sensitive analysis measured five sources of subject error variance, four independent, additive sources of error variance: imperfect color-attention filters; a Bayesian-like bias towards a central tendency; storage, retrieval, and cursor misplacement error; a large residual error due mostly to inefficient encoding; and fifth, an interactive sourceerror in all four components that increases when multiple centroid judgments versus a single centroid judgment are required on each trial. Significance statementAn important brain process is a salience map, a representation of the relative importance (salience) of the locations of visual space. It is needed to guide where to look next, for computing the center (technically "centroid") of a cluster of items, and for other important computations. Here we show that in a brief flash of dots of three different colors, randomly interleaved, subjects can compute all three centroids. As a single salience map cannot discriminate dots of different colors, accurately reporting three centroids demonstrates that subjects have not just one, as is commonly believed, but at least three salience maps.

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Prefrontal Control of Proactive and Reactive Mechanisms of Visual Suppression

et al. 2021

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In everyday life, we are continuously struggling at focusing on our current goals while at the same time avoiding distractions. Attention is the neuro-cognitive process devoted to the selection of behaviorally relevant sensory information while at the same time preventing distraction by irrelevant information. Distraction can be prevented proactively, by strategically prioritizing task-relevant information at the expense of irrelevant information, or reactively, by suppressing the ongoing processing of distractors. The distinctive neuronal signature of these suppressive mechanisms is still largely unknown. Thanks to machine-learning decoding methods applied to prefrontal cortical activity, we monitor the dynamic spatial attention with an unprecedented spatial and temporal resolution. We first identify independent behavioral and neuronal signatures for long-term (learning-based spatial prioritization) and short-term (dynamic spatial attention) mechanisms. We then identify distinct behavioral and neuronal signatures for proactive and reactive suppression mechanisms. We find that while distracting task-relevant information is suppressed proactively, task-irrelevant information is suppressed reactively. Critically, we show that distractor suppression, whether proactive or reactive, strongly depends on the implementation of both long-term and short-term mechanisms of selection. Overall, we provide a unified neuro-cognitive framework describing how the prefrontal cortex deals with distractors in order to flexibly optimize behavior in dynamic environments.

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Variation in target and distractor heterogeneity impacts performance in the centroid task

Cited by 5 publications

References 31 publications

Color scrambles reveal Red and Green half-axis mechanisms plus a mechanism selective for low chromatic contrast

Color scrambles reveal Red and Green half-axis mechanisms plus a mechanism selective for low chromatic contrast

Multiple concurrent centroid judgments imply multiple within-group salience maps

Prefrontal Control of Proactive and Reactive Mechanisms of Visual Suppression

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